Telephone system



0d. .1, 19466 MALONE-Y 2,408,432

TELEPHONE SYSTEM Filed May 23, 1945 2 Sheets-Sheet 1 1'0 MARKER TRUNK //v ENTOR M E MALONE Y C. WLW

A TTORNE V EEEEEE ME Oct. 1, 1946. M. E; MALONEY TELEPHONE SYSTEM 2 Sheets-Sheet 2 Filed May 25, 1945 lNVE/VTOR By M 5 MALO/VEY- ATTORNEY Patented on. 1, 1946 TELEPHONE SESTEM Martin. E. Matlonszo Flushing N. X3, assignor to. Bell. Telephone Laboratories lnccrnorated, New York, .N. Y, a,. .corpor ation. oihtemYQIk Y Application-May 1945, Serial No. sssgscr 1 r 'Thisinvention relatesztotollatelephone systems and has iorritsobjectuto facilitate the completion: of tollconnections. during busy calling periods.

More specifically, the invention contemplates anzimprovementon the automatic switching an. rangements disclosed. and claimed in the patent application, Serial, N o. .5 50;0'Z:0,,.of B. "McKim .and- 0. Myers. filed. August 1:8; 19.44, patented Aug. '14, 194:5; .No. 2,382,393;

In1that application is shown a. toll. emceell-nipped automatic. switches of :the cross bar type, in which calls incoming to the oilice areextend'ed to. toutgoing trunks :under the: contmioi register" senders and markers, the former of which receive the designation of the wanted 11 Claims. (curse-121 subscriber either-directly irom: the local: tol'l-oper atoror over the: incoming trunk fromthe toll operator at. the. calling vomce.

During periodssof snormal: traific, the marker receiysesthedesignation or the wanted. ofiice f-rom the sender, tests. tor and selects an idle trunk outgoing to that; oflice, operates the: necessary crossbar switches to; connect theincoming trunk With; ,:the..se1-ected outgoing trunk and releases; having: given. the sender .anyxinformation necessary :tior its further -.operation. However, all o the nun out oingtd. the wanted oifice are- .busy, f the 'rmarker connects the incoming; trunk' to one .lof a number of overflow trunks, individual to wanted. group of outgoing trunks, over which the calling toll operator receivesa flashing overflow :signal. When an outgoing trunk -be-. comes; idle, the rate \of flashing; 'i's changed-to indicate a reorder and the calling toll operator;

designation of the outgoing trunk grouptep sender connected with the associated-incomingtrunk.

trunk: and a rehuntsisnaiis transmitted; to; th sender; The rehunt signed causes the sender-tearrange. its circuitsrtc receive. pulses. from the outgoing and oi. the trunk and alsoto prepare. to: transmit, it necesseryi. the. proper desi nation for extending the. call. to .an. .cnereim's positionat-thewianted .oflice...

These and other features of the inyentionsrzill be..more-clear1y understood from a consideratim of, the following .rlescription mead in connection with the-drawings, in which:

Fig; 1 .showsta'psrtsoiincomins trunk cin cuit. and. an .cnerflcw trunk-.andcode. generator embodying: the *presentinventicn: and,

Fig. 2- show of .a sender and-a :merlier iorcarrying: ontrlthe restores of. theinvention.

The drawings are, in part, skeletenized shew! ingsof the circuits of: theaters-mentioned.snpl

cnticnctMcKjmsndMyera; ,Reierencc is made n thatcanplicationior a. disclosure of the som Piste. equipment .and. where pnssibl th s me reference @charaeters here. emplo ed.

erencennmeralslessthanimthiindred ident yadded ecminmenhv 5 .Anincoming callyover a trunk; such sis-shown at the-:ieitcfiig. 1, isrindicated'hvtheconnection of ground to-conductor 1:00: iIILESPOBSe tothe operation ofv a. composite. signalin circuit snot showmsmnder thezccntrolact the-calling:toolcpere ator-at the distant office. Ground on conductor mo, completes; a circuit: extending: over .11 back contactoi relay $20: to; :therwindins. 0f -1re1a-y 618. and battery. Relay 15283010585: arr-obvious circuitfor relay 5221 which. looks. inc-ground sityits own.

. contact, closesia .holdina'nircuitt for Tel-a3! .521 to:

conductor 1 00 and connects ground 1W6! a back contactacf relay 452D to. conductor 1658.1;0 operate Anotherieature or the invention lies in means for-transmitting the'recrder signaT-to a plurality of incoming trunkstogether with means tonssocia te the designation transmittingmeans with n single calling trunk, changing the reorder signal backto an overflow's'igna-l =f'or the-other caliing trunks. 1

Another feature of the inventionlies in means to set-up a record in an incoming trunk when that trunk has been connected toan overflow trunk. When-the -operatorrering's in response :to the reorder signal, a .sender' is attached to the the linkzstartzrelay- :200. and: :cause the, operationof the sender ili-nk 20%]. to, conmact.'1'.'l:\e..itrnnk qi Ei'g. l-withanidle sender such asqthe nnesherm in-part in Fig.2..

When this connection is completed, :a circuit is: closed from battery through the, "windings. ;of relays Brand: 1315', conductor 680 through sender link-L201 .eto conductor 2.4.54 and thence over a =.back. contact.oi relay fllts windingsnof relay 034:0 groundkat the hack. contact ofrrelayIl-ltl...

Relay flnloperatesdn this-circuit zbutrelays .688; andi l-il cannot, .due toLthe high resistance acf: :the-

left winding of relay 2M3. Relay- 2503 -;nperates. relay 2402 which operates- .relay' 24M .and. scene nects..-.a substitute --gro1md to. the Jisht winding of relay Mus.v Relay'ilmconnects r und conductor. .2 455. whichextendszthmngh. the sender link 2015 to conductor 64. wmdingof relay 620 permit that relay to operate.

resistanceleft"winding "of relay 2403 to permit relays B and EH to operate. Relays 609 and M5 disconnect the incoming and outgoing line conductors, relay 609 extending the incoming conductors of the upper channel to conductors EBI and 682, while relay 615 bridges resistance- 632 across the incoming tip ancl rinlg' conductors of the lower channel. The outgoing tip and ring conductors of the upper channelijareconnected t0 conductors 535 and 668 while those ofthe lower channel are connected to conductors 631" and 608.

Theoperation of the sender inreceiving the numberof the wanted subscribe'r and transferring thebfiice code toa marker takes place .as described in the above-identified McKim-Myers patent. The marker identifies 1 the group of trunks leading'to the .wanted office and attempts to test them, In the manner setforth in the McKim Myers patent, if'all of the trunks 'I are busy; a relay such as..relay :402, isi-im'mediately' operated which causes the. marker. to test for. an idle overflow trunkiand operatethe. outgoing link switches 500 to connect theincoming trunk Wlth'theiDVelfiDW tllll'lk'at the right ofFig. 1. The operation. of relay 402- also transmits. a signal to thesender which: operatesrelay2l202 to tell-thesender that -the"call hasnbeen extended to an overflowtrunk. a A

After the marker has'tested the overflow trunk and found it idle itconnects groundto conductor I02, closing a 'circuitover a back contact ofrelay I'03"'to the winding of relay I04 and battery. Relay I04 connects battery through the winding o'f'relay I03 over a front contact of relay I04 and a make-before-break contact ofarelay I03 to the'simplex circuit over. the' lower channel of the .trunk,'t-hrough switches 500 and contacts of, relay 6I5 to conductors 631.and 668. i 1' When the marker hasfcornpleted its function the markerrelease relay 203 is operated, in turn,

operatingirelay 250I.' Relay 250I operates,=.locks and closes a circuit-from ground over its lower ontact,-uppe'r winding of relay 2H0, 'ove'r conductors 2353 and 235cm parallel, through the sender link to conductors 56! and 668. If: the connection has been .completed, relay-2'IIO operates, in'turn operating relay'2809 which operates, locks; and connects the .low resistance lower winding of relay 2'll0'in parallel with the upper winding 'of*relay-21l0, reducing the re-' sistarice' in series withirelay I03'suificiently to Relay" I03 locks undertthe'control of relay IMandzextends the simplex circuit'through resistance I05 and the back. contact of relay- I to conductor ilifl'to' which "interrupted groundi's connected, at a rate to" indicate an overflow condition, by the overflow :circuit." Relay I03 also connectspthe tip and ring'conductors of the lower channel through condensersl 08 and IDS-and over contacts of relay I30 to conductors III! and III leading to a jack at the delay quotation board, the operation of which is fully disclosed'in -the McKim-Myers, patent, previously mentioned, Relay I03 also connects ground over the back contact of relay I30 to conductors II2 and -I I3 to control the and 6I5, causing these relays to release.

relay 202- was operated to tell the sender that functions of the overflow circuit. In addition it connects ground to conductor I02 to mark this overflow trunk busy to any marker which may be testing in this group.

In the sender, the connection of ground to the simplex circuit causes the release of relay 2IIO, closing a circuit from ground over the back contactofre'lay 2;II0, front contact of relay 2809 to the winding of relay 2109 and battery. Relay 2709 opens the operating circuit of relays 609 Since the call had been extended to an overflow trunk,

as soon as relay 6I5 releases, relay 2109 closes a circuit from ground over its front contact, front contact of=relay 202, through the sender link 20I to conductor-665, back contact of relay 6I5, norassociated with the overflow'trunk of Fig. 1,'be-

comes idle, the rate of the flash transmitted over the-trunk is changed as a reorder signal. As above noted, as many asfour incoming trunks may be connected to the overflow circuit, each one having a pair of relays like relays-I20 and I30; Conductor I01 to which'the'fiashing "ground is connected extends in parallel over back con tacts of relays I30, vIll, I33..;to:'the trunks con-- nected thereto and therefore four calling toll 0perators may observe the reorder signal'and op-' crate their compositesignal circuits to attempt to seize the trunk which has, become idle.

In the trunk circuit of Fig. l, relays 620 and 62I are locked. Therecall'operation' momentarily removes groundfromconductor I00 releasing and reoperating relay 628.. While relay 628 is re-" leased it, operates relayy605 over a backcontact of relay 6I5. Since relay 'IOI was operated and locked, relay 6.05 now locks over the front contact of relay IOI and this locking ground is extended over'a second front contact of relay IOI to thestart conductor 663, operating the'senderlinkto connect a sender with the trunk-asp'reviously described. 1

Since relay $20 is locked to ground at the contact of relay 62-1,, ground appears on-conductor 6.64 which is extended through the sender link 20I to conductor 2455 and over the back contact of relay, 2,402 to the winding of relay 204 and battery. Relay'204 operates in-this circuit and looks so that it remains operated after relay 2402 opens its-operating circuit. I c 7 When relay 26H operates, with relay 20,4 opgrated, a circuit is closed from ground in the alternating current receiving circuit 206, front contact of relay 26I I,-'fron t contact of relay 204 winding of relay 205 and battery; Relay 205 disconnects the receiving circuit 205 from-the incoming end of the trunkand-connects it to con-;- ductors 2350 and 2353, ready to receive pulses from the outgoing end of the trunk. Relay 205 also" connects battery and ground to conductors 2352and 235I. Whenrelays 609 and GIS are operated in the manner above described, they release; relay I0, I

vided in connection with trunk groups requiring more code digits.

, What .is claimed is: r

1. In a telephone system,-a toll oflice, trunks incoming to said oflice, trunks outgoing from said oflice arranged in groups in accordance with ofiice codes, each group including an overflow trunk individual thereto, control equipment, means responsive to a call over one of said incoming trunks for connecting control equipment with said trunk, means in said control equipment for registering an oflice code, means in said control equipment responsive to the registration of a code ior extending said incoming trunk to an idle one of the corresponding group of outgoing trunks or to the overflow trunk individual thereto and thereupon releasing from said'incoming trunk, means responsive to a recall over said incoming trunk to reconnect control equipment with said trunk and means in said overflow trunk for transmitting the code of the trunk group to said reconnected control equipment.

2. In a telephone system, a toll office, trunks incoming to said ofiice, trunks outgoing from said oflice arranged in groups in accordance with ofiice codes, each group including an overflow trunk individual thereto, control equipment, means responsive to a call over one of said incoming trunks for connecting control equipment with said trunk, mean in said control equipment for registering an oflice code, means in said control equipment responsive to the registration of a code for extending said incoming trunk to an idle one of the corresponding group of outgoing trunks or to the overflow trunk individual thereto and thereupon releasing from said incoming-trunk, means responsive to a recall over said incoming trunk to reconnect control equipment with said trunk and means in said overflow trunk responsive to said reconnection for transmitting the code of the trunkigroup to saidreconnected control equipment;

3. In a telephone system, a toll oflice, trunks incoming to said oflice, trunks outgoing from said office arranged in groups in accordance with oiflce codes, each group including an overflow trunk individual thereto, control equipment, means responsive to a call over one of said incoming trunks for connecting control equipment with said trunk, means in said control equipment for registering anofflce code, means in said control equipment responsive to the registration of a code for extending said incoming trunk to an idle one of the corresponding group of outgoing trunks or to the overflow trunk individual thereto and thereupon releasing from said incoming trunk, overflow indicating means operated in said trunk prior to the release of said control equipment if said trunk is connected to an overflow trunk, and means responsive to a recall over said incoming trunk if said overflow indicating means is operated to reconnect control equipment with said trunk.

4. In a telephone system, a toll ofiice, trunks incoming to said ofiice, trunks outgoing from said oflice arranged in groups in accordance with oflice codes, each group including an overflow trunk individual thereto, control equipment, means responsive to a call over one of said incoming trunks for connecting control equipment with said trunk, means in said control equipment'ior registering an office code, means in said control equipment responsive to the registration of a code for extending said incoming trunk to an idle one of the Corresponding g p of outgoing trunks or to the overflow trunk individual thereto and thereupon releasing from said incoming trunk, overflow indicating means operated in said trunk prior to the release of said control equipment if said trunk is connected to an overflow trunk, means responsive to a recall over said incoming trunk if said overflow indicating means is operated'to reconnect control equipment with said trunk, and means in said overflow trunk for transmitting the code of the trunk group to said reconnected control equipment. 7

5. In a telephonesystem," a toll ,ofilce, trunks incoming to said ofllce, trunks outgoing from said office arranged in groups in accordance with oflice codes, each group including an overflow trunk individual thereto, control equipment, means responsive to a call over one of said incoming trunks for connecting control equipment with said trunk, means in said control equipment for registering an oflice code, means normally effective to connect said registering means to theincoming end of said trunk, means in said control equipment responsive tothe registration of a code over the incoming end of said trunk for extending said incoming trunk to an idle one of the corresponding group of outgoing trunks or to the overflow trunk individual thereto and thereupon releasingfrom said incoming trunk, means responsive to a recall over said incoming trunk .to reconnect control equipment with said trunk, means responsive to said reconnection to connect said registering means to the outgoing end of said trunk, and means in said overflow trunk for transmitting the code of the trunk group to said reconnected control equipment.

6. In a telephone system, a toll oflice, trunks incoming to said office, trunks outgoing from said ofiice arranged in groups in accordance with oflice codes, each group including an overflow trunk individual thereto, control equipment, means responsive to a call over one of said incoming trunks for connecting control equipment with said trunk, means-in said control equipment for registering anoiiice code, means normally effective to connect said registering means to the incoming end of saidtrunk, means in said control equipment responsive to the registration of a code over the incoming end of said trunk for extending said incoming trunk to anidle one of the corresponding group of outgoing trunks or to the overflow trunk individual thereto and thereupon releasing from said incoming trunk, overflow indicating means operated in said trunk prior to the release of said control equipment if said trunk is connected to an overflow trunk, means responsive to a recall over said incoming trunk if said over flow indicating means is operated to reconnect control equipment with said trunk, means responsive to said reconnection to connect said registering means to the outgoing end of said trunk, and means in said overflow trunk for transmitting the code of the trunk group to said reconnected control equipment.

7. In a telephone system, a toll otflce, trunks incoming to said ofiice, trunks outgoing from said oflice, said outgoing trunks arranged in groups, an overflow trunk individual to each group, means effective when all of a group of outgoing trunks are busy to connect a plurality of incoming trunks to the overflow trunks individual to said group of outgoing trunks, means to transmit an overflow signal over said overflow trunk to said plurality of incoming trunks,. means responsive to one of said group of outgoing trunks becoming idle to transmit a reorder signal .over said overflow trunk to said plurality of incoming trunks, means responsive to" a recall over one of said incoming trunks to transmit an identification of said group of outgoing trunks to said one incoming trunk and means simultaneously effective to again transmit an overflow signal to the others of said plurality of incoming trunks.

8. In a telephone system, a toll office, trunks incoming to said oflice, trunks outgoing from said ofiice, said outgoing trunks arranged in groups, an overflow trunk individual to each group, means effective when all of a group of outgoing trunks are busy to connect a plurality of incoming trunks to the overflow trunk individual to said group of outgoing trunks, means to transmit an overflow signal over said overflow trunk to said I plurality of incoming trunks, means responsive to one of said group of outgoing trunks becoming idle to transmit a reorder signal over said overflow trunk to said plurality of incoming trunks, means responsive to a recallover one of said incoming trunks .to transmit an identification of to said group of outgoing trunks, means to trans-- mit an overflow signal over said overflow trunk to said plurality of incoming trunks, code generatingmeans individual to said overflow trunk, means responsive to one of said group of outgoing trunks becoming idle to transmit a reorder signal over said overflow trunk to said plurality of incoming trunks, means responsive to a recall over one of said incoming trunks to connect said code generating means with said one incoming trunk to transmit an identification of said group of outgoing trunks to said one incoming trunk, and means under the control of said connecting means to automatically transmit an overflow signal to the others of said plurality of trunks during the transmission of said identification to said one trunk.

'10. In a telephone system, a toll oflice, trunks incoming to said oflice, trunks outgoing from said office arranged in groups in accordance with ofiice codes, each group including an overflow trunk individual thereto, control equipment, means responsive to a call over one of said incoming trunks for connecting control equipment with said trunk, means in said control equipment for registering an'oflice code, means in said control equipment responsive to the registration of a code for extending said incoming trunk to the corresponding overflow trunk if all of the outgoing trunks are busy and thereupon releasing from said incoming trunk, means to connect a plurality of other incoming trunks to said overflow trunk, means to transmit a flashing overflow signal over said overflow trunk to all of said in- 1 coming trunks, means responsive to one of said group of outgoing trunks becoming idle for transmitting a reorder signal over said overflow trunk to all of said incoming trunks, means responsive to a recall over one of said incoming trunks to'reconnect control equipment with said one trunk, code generating means individual to said overflow trunk, means under the control of said control equipment to connect said code generating means with said one incoming trunk to transmit the code of the outgoing trunk group to said reconnected control equipment and means responsive to said code generator connecting means to again transmit said flashing overflow signal to said other incoming trunks.

11. In a telephone system, a toll office, trunks incoming to said office, trunks outgoing from said office arranged in groups in accordance with oflice codes, each group includin an overflow trunk individual thereto, control equipment, means responsive to a call over one of said incoming trunks for connecting control equipment with said trunk, means in said control equipment for registering an office code, means in said control equipment responsive to the registration of a code for extending said incoming trunk to the corresponding overflow trunk if all of the outgoing trunks are busy and thereupon releasing from said incoming trunk, means to connect a plurality of other incoming trunks to said overflow trunk, means to transmit a flashing overflow signal over said overflow trunk to all of said incoming trunks, means responsive to one of said group of outgoing trunks'becoming idle for transmitting a reorder signal over said overflow trunk to all of said incoming trunks, means responsive to a recall over one of said incoming trunks to reconnect control equipment with said one trunk, code generating means individual to said overflow trunk, means under the control of said control equipment to connect said code generating means with said one incoming trunk to transmit the code of the outgoing trunk group to said reconnected control equipment and means responsive to said code generator connecting 

